Roger Federer is looking to regain the aura of invincibility he once owned and says a fifth consecutive US Open tennis title would be just the thing to put him back atop the tennis world.
The 12-time grand slam champion has won his 30th consecutive US Open match, defeating Czech Radek Stepanek in straight sets to reach the fourth round of the year's last major tournament.
Federer was dethroned from the world number one spot two weeks ago by Spain's Rafael Nadal after owning the top spot for more than four years but feels he's only one grand slam away from getting back on track.
Serbian third seed Novak Djokovic tookl four hours to quell big-serving Croatian teen-ager Marin Cilic in four sets to reach the fourth round while women's world number two JelenaJankovic won in three sets as she looks for her first major title, advancing to the quarter finals for the third year running.
Olympic champion Elena Dementiava has also advanced with a straight sets win.